3D PUFF EMBROIDERY3D puff (3D foam) is a technique where 2-4mm foam is placed under the top stitching of a design to raise or "puff" the surface, giving a 3D look to your embroidery designs. It is most commonly used on structured hats with logos that are simple. 3D puff does not work well on unstructured hats or with logos that have small details. You can also mix 3D puff with regular, flat sewing in most designs.